hugetlb: fix handling of parse errors in sysfs

When parsing changes to the huge page pool sizes made from userspace via
the sysfs interface, bogus input values are being covered up by
nr_hugepages_store_common and nr_overcommit_hugepages_store returning 0
when strict_strtoul returns an error.  This can cause an infinite loop in
the nr_hugepages_store code.  This patch changes the return value for
these functions to -EINVAL when strict_strtoul returns an error.

Signed-off-by: Eric B Munson <emunson@mgebm.net>
Reported-by: CAI Qian <caiqian@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Eric B Munson <emunson@mgebm.net>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Nishanth Aravamudan <nacc@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index ce8e5bb6f031d20be5c4102bb50e7f50c95664d0..bb0b7c128015f5cbb9f23d78b88c4b5e6eec2e7b 100644 (file)
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1375,10 +1375,8 @@ static ssize_t nr_hugepages_store_common(bool obey_mempolicy,
        NODEMASK_ALLOC(nodemask_t, nodes_allowed, GFP_KERNEL | __GFP_NORETRY);
 
        err = strict_strtoul(buf, 10, &count);
-       if (err) {
-               err = 0;                /* This seems wrong */
+       if (err)
                goto out;
-       }
 
        h = kobj_to_hstate(kobj, &nid);
        if (h->order >= MAX_ORDER) {
@@ -1469,7 +1467,7 @@ static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj,
 
        err = strict_strtoul(buf, 10, &input);
        if (err)
-               return 0;
+               return err;
 
        spin_lock(&hugetlb_lock);
        h->nr_overcommit_huge_pages = input;